Exclude autogenerated files from rerun-if-changed directives

build.rs

@@ -1,21 +1,54 @@
 use std::env;
 use std::path::{Path, PathBuf};
 
-fn generate_bindings<'a>(include_paths: impl Iterator<Item = &'a Path>) {
+/// Used to exclude autogenerated files in the output dir from `cargo:rerun-if-changed` directives.
+#[derive(Debug)]
+pub struct CustomCargoCallbacks {
+    exclude_dir: Option<PathBuf>,
+}
+
+impl bindgen::callbacks::ParseCallbacks for CustomCargoCallbacks {
+    fn header_file(&self, filename: &str) {
+        if matches!(&self.exclude_dir, Some(exclude_dir) if Path::new(filename).starts_with(exclude_dir))
+        {
+            return;
+        }
+        println!("cargo:rerun-if-changed={filename}");
+    }
+
+    fn include_file(&self, filename: &str) {
+        if matches!(&self.exclude_dir, Some(exclude_dir) if Path::new(filename).starts_with(exclude_dir))
+        {
+            return;
+        }
+        println!("cargo:rerun-if-changed={filename}");
+    }
+
+    fn read_env_var(&self, key: &str) {
+        println!("cargo:rerun-if-env-changed={key}");
+    }
+}
+
+fn generate_bindings<'a>(
+    exclude_dir: Option<PathBuf>,
+    include_paths: impl IntoIterator<Item = &'a Path>,
+) {
     // The bindgen::Builder is the main entry point
     // to bindgen, and lets you build up options for
     // the resulting bindings.
-    let builder = include_paths.fold(bindgen::Builder::default(), |builder, path| {
-        builder.clang_arg(format!("-I{}", path.to_string_lossy()))
-    });
+    let builder = include_paths
+        .into_iter()
+        .fold(bindgen::Builder::default(), |builder, path| {
+            builder.clang_arg(format!("-I{}", path.to_string_lossy()))
+        });
     let c_bindings = builder
         // The input header we would like to generate bindings for.
         // This is a trivial wrapper header so that the HiGHS headers
         // can be discovered from the include path.
         .header("wrapper.h")
         // Tell cargo to invalidate the built crate whenever any of the
         // included header files changed.
-        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
+        .parse_callbacks(Box::new(CustomCargoCallbacks { exclude_dir }))
         // Finish the builder and generate the bindings.
         .generate()
         // Unwrap the Result and panic on failure.
@@ -51,7 +84,7 @@ fn build() -> bool {
         .build();
 
     let include_path = dst.join("include").join("highs");
-    generate_bindings(Some(include_path.as_path()).into_iter());
+    generate_bindings(Some(dst.clone()), [include_path.as_path()]);
 
     println!("cargo:rustc-link-search=native={}/lib", dst.display());
     println!("cargo:rustc-link-search=native={}/lib64", dst.display());
@@ -90,7 +123,7 @@ fn discover() -> bool {
         Err(_e) => return false,
     };
 
-    generate_bindings(lib.include_paths.iter().map(|p| p.as_path()));
+    generate_bindings(None, lib.include_paths.iter().map(|p| p.as_path()));
 
     true
 }